Yeah. Stealth C is the hardest to win with (Or do anything with except die), but you already said that. I can say the vortex on hard WILL BE TORTURE. It took me countless tries to get to sector 8 with it, so I can't imagine winning. You have been warned.

Yeah. The time limit of that backup battery is like a ticking clock to your doom. Get it right the first time or say goodbye. And when you do get the power you need, the weapons aren't that great. The charge ion can barely take down 2 shields and the beam drone is sort of good, but is useless with shields enabled.And the Engi B can't even manage to take down 2 shields. SAD.